The present invention relates to a method for making a protective device for guardrails and to a protective device for guardrails.
A guardrail is a highway safety barrier consisting of uprights, fixing means and longitudinal rails. The latter consist of one or more shaped plates with predetermined height which form a guardrail bumper or buffer zone. The plates are rigidly bound, by the fixing means, at predetermined heights from the ground, to uprights, that is to say, vertical supports, positioned at regular distances from each other designed to support the plates and hold them in position. Moreover, in some guardrails there is a lower longitudinal element, parallel with the plates, positioned at a predetermined height from the ground and bound to the uprights under the plates. The lower longitudinal element is also known as an anti-intrusion element.
Guardrails are positioned along the edges of roadways to contain and correct the trajectory of vehicles leaving the roadway in the event of an accident.
Although the longitudinal rails efficiently keep cars which skid in accidents on the roadway, they are not as effective if a motorcycle skids.
In most cases, a skid on a two-wheeled vehicle is immediately followed by the rider falling.
Since the longitudinal rails of the guardrails are positioned at heights corresponding to the height of the center of gravity of the most common types of cars, they are too high to stop a two-wheeled vehicle that is sliding on the ground.
For this reason, as indicated above, some guardrails are equipped with anti-intrusion elements located below the longitudinal rail.
However, although guardrails, particularly those with an anti-intrusion element, can stop or divert any vehicle that is out of control, they are extremely dangerous, if not fatal, for the riders of two-wheeled vehicles who lose control of the vehicle and consequently fall.
The shape and bending of the sheet metal used for the uprights and the rails, the fixing elements used (bolts, screws or other devices) and the reflectors usually fixed to the rails to make them more visible at night, all mean that guardrails present numerous sharp, cutting edges. Obviously, said edges are a serious threat to motorcyclists who fall from their two-wheeled vehicle. Quite frequently following such collisions against guardrails, motorcyclists or cyclists suffer permanent disability or serious injury caused by the presence of these sharp, cutting edges.
Moreover, guardrails made from sheet metal are now so widely used that their substitution with other barrier types (for example, those made from concrete) which do not present sharp, cutting and potentially hazardous edges is considered too complicated and expensive.